Managed Airflow upgrades pip to 26.2.2, changing custom PyPI package installs

(Airflow 3.3.1, 3.2.2, and 2.11.1) Upgraded the pip package from version 23.2.1 to version 26.2.2. This update is available in Managed Airflow (Gen 3) builds composer-3-airflow-3.3.1-build.8, composer-3-airflow-3.2.2-build.12, and composer-3-airflow-2.11.1-build.25 and later, and in the Managed Airflow (Gen 2) image composer-2.18.0-airflow-2.11.1 and later.

This version includes security fixes and changes how custom PyPI packages are installed:

• PEP 440 version specifiers: pip 26.2.2 enforces PEP 440 compliance and supports the .* wildcard only with == and !=. For example, use gcsfs>=0.8 instead of gcsfs>=0.8.*.
• Isolated source builds: source packages (.tar.gz) are always built in an isolated environment. If you install source packages from a private repository that is your only package index, make sure that the repository contains precompiled wheel packages (.whl) for setuptools and any other build dependencies (listed under [build-system] requires in pyproject.toml). Alternatively, publish your packages as .whl packages. As a temporary workaround to disable build isolation, add no-build-isolation = false to the [global] section of your pip.conf file. This workaround works only if the build dependencies are already installed in your environment.
• Legacy pkg_resources builds: older source packages that rely on pkg_resources might fail to build. Use newer package versions with precompiled .whl packages, or for your own private packages, build them as .whl packages or update their build scripts so that they don't use the legacy pkg_resources module.

Make sure that your custom PyPI packages are compatible with these changes before you upgrade your environment. If the installation of PyPI packages fails during an upgrade, your environment keeps running with its current version and packages.